Generally, a moving image is encoded when transmitted or stored to increase the transmission efficiency and the compression efficiency. Upon receipt of the encoded moving image, the receiving side decodes the image, and performs noise reduction (NR) to reduce block noise/mosquito noise occurring due to encoding and sharpening to improve image quality on the decoded image to reproduce it.
For example, Japanese Patent Application Publication (KOKAI) No. 2006-135571 discloses a conventional technology for noise reduction and sharpening. According to the conventional technology, image quality correction such as contour correction and noise reduction is performed based on information related to frame encoding obtained upon decoding.
It is difficult to perform both sharpening and noise reduction to reduce block noise/mosquito noise together. With the conventional technology, noise generated by encoding cannot be reduced without influence on the improvement of image quality by sharpening.